Adhesives for bonding fuels and insulation into rocket motor casings in the prior art have often contained asbestos to make the adhesives more resistant to the hot gases in the rocket motor. These adhesives have three functions: first to insulate the fuel against heating due to air friction, second to insulate the casing from the heat of the burning fuel and third to bond the fuel to the case. It is undesirable to have voids between the fuel and the combustion chamber wall since such voids could permit combustion at undesirable times and places, impairing the efficiency of the rocket and endangering the integrity of the combustion chamber. The possible danger to the health of workers with asbestos makes it desirable to find other ways of accomplishing the same goals of good bonding combined with good insulation properties without the use of asbestos.